Voter registration by party only applies to primary elections, and does not apply to general elections.

In many machine-dominated Democrat states and cities it is not uncommon for reform-minded Democrats to register as Republicans, as it historically has been impossible to reform the Democrat party from within, and local Republican parties may be virtually non-existent. Their Republican registration, vote, or candidacy can often be seen a protest against Democrat corruption. These voters and candidates are often characterized as RINOs.